Magnetic alloy



Patented Sept. 8, 1925.

' WILLOUGHBY STATHAM SMITH, OF NE GARNETT, or snvnnonxs, ENGLAND.

WTON POPIPLEFORD, AND HENRY JOSEPH MAGNETIC ALLOY.

No Drawing. Application filed January T 0 all whom it may concern:

Be it known that we, IVILLOUGIIBY STAT- HAM SM1'rn,'a subject of the King of Great Britain, residing at Benchams, Newton Poppleford, Devonshire, England, and HENRY JosErH GARNETT, a subject of the King of Great Britain, residing at Lymne, Solefields, Sevenoaks, Kent, England, have invented a new and useful Improvement in Magnetic Alloys, of which the following is a specification.

This invention relates to the production of alloys possessing a high magnetic per-- nieability especially at low magnetizing forces.

It is well known that it is desirable to add inductance to telegraphic and telephonic c-a bles and this has before been done by Wrapping around the core of the cable an iron tape or Wire.

Many research workers have been investigating the properties of various alloys, especially those ofonickel and iron, with a view to discovering an allo that should be suitable for this urpose. 11 our researches we have found t at an alloy may be made of nickel, copper and iron, which has a low hysteresis loss with a very high permeability at low magnetizing forces such as those plresent in telegraphic and telephonic ca- According to our invention we make an alloy of nickel, iron, copper and manganese, the nickel being at least 71%, the iron about 20% and the copper about 5% with a small quantity of manganese to render the alloy more easy to forge.

In some cases, however, we may employ 15% to 25% copper with 49% to 71% nickel,

17% to'25% iron and manganese as before.

In order also to increase the electrical re sistance of the alloy We preferably add to it a fourth element which may be tungsten, chromium, silicon, vanadium, titanium, molybdenum or aluminium; the amount of this fourth element ,is small compared to a the amount of copper and is preferably less than 1%, since'the addition of more than 1% of this fourth element, though increas- 10, 1924. Serial No. 685,432.

The followin are exam ales of allo s made L in accordance with out invent-ion:-

has an initial magnetic permeability of .3200.

An alloy consisting of 1 Per cent.

Nickel 49.5 Iron 25.0 Copper 25.0 Manganese 0.5

lltS an initial magnetic permeability of l 00. 5

These alloys are sensitive to heat-treatment and should be annealed by heating to a considerable temperature and then cooled. This may conveniently be done by passing a Wire or tape formed of the alloy through a tube heated electrically and allowing the wire or tape to cool rapidly as it issues from the tube.

If the correct temperature has not been used the magnetic properties will not be fully developed.

Exam 1e Alloy o. 1 when heated to 890 C. and cooled in air has a permeability. of 5300, but when heated to 730 C. only 3800.

Further, the annealing maybe adjusted to give either (a; Maximum initial permeability, or

(1) Maximum permeability at magnetic saturation, and

(a) Low or highfields for magnetic saturation.

Moreover, when correctly annealed for high initial. permeability, the alloys have iron 25%,

low hysteresis losses rarying from 50 to 150 ergs per cubic centimetre with a maximum field of .25 C. G

What we 01 1 Analloy 71%, iron 17% to 25%,' and. copper 2. An alloy. consisting ofnickel 49.5%,

copper 25% 11 alloy consisting ofnickel 65.5%, I iron 17 copper 17% and manganese .5%.

and manganese .5

"4. An alloy consisting of nickel 49% to 71%, iron 17% to 25%,"c0pper 15% to 25% and a-small 5. An allo 71%, iron 17% to 25%, copper 15% and a small tungsten.

quantity of manganese.

y comprising nickel 49%" to to 25%, quantity of manganese and comprising nickel 49% to 6. An alloy comprising nickel 49% to 71%, iron 17% and tungsten.

.7. An alloy comprising nickel 49% to copper 15% to 25% adapted to increase of the alloy.

element adapted to. increase. the electrical resistance of the alloy.

In testimony that we claim the foregoing as our invention we have signed our name this 14th day of December, 1923.

WILLOUGHBY STATHAM SMITH. RY JOSEPH GARNETT.

to 25%, copper 15% to 25% 

